OBJECTIVES: 1) To determine the accuracy of fluorescence bronchoscopy to localize carcinoma in situ in 100 or more patients with occult lung cancer (chest X-ray negative, sputum positive). 2. To localize cancer lesions that are invisible to white light bronchoscopy, in 200 or more patients who have a subtle or small visible lesion, but have lesions only visible by their fluorescence in other areas or in the opposite lung, or extending along the bronchus from the main site or in the main carina. 3. To develop methods to fluorescence bronchoscopy visualization of localized fluorescence imaging and viewing, methods of qualitating fluorescence intensity and for subtracting background to enhance localization, and to develop an integrated optimal clinical instrument and method, also applicable to localization of early cancer in other organ systems - GI, GU. 4. To develop methods for delivery of doses of light for photoradiation therapy of whitelight visible and fluorescence visualized bronchial cancer, with sites sensitized by hematoporphyrin derivative. To initiate clinical trials of curative photoradiation therapy of carcinoma in situ, and palliative therapy for non-operable obstructing endobronchial cancers.